Choriogonadotropin Alfa

Choriogonadotropin alfa is a laboratory-made version of human chorionic gonadotropin, a glycoprotein hormone naturally produced by placental trophoblast cells during pregnancy. Like the other gonadotropins, the hormone is built from two subunits, an alpha chain shared across the glycoprotein hormone family and a beta chain that gives it its specific identity, and it is structurally and functionally close to luteinizing hormone (LH) ^[1].

Historically, hCG for medical use was purified from the urine of pregnant women, which yielded a variable and impurity-laden product. Choriogonadotropin alfa is instead expressed in cultured mammalian cells through recombinant DNA technology, producing a highly consistent, high-purity hormone that can be dosed by mass and delivered as a ready-to-use subcutaneous injection ^[3].

Its main role is in assisted reproduction. During controlled ovarian stimulation for procedures such as in vitro fertilization, a single injection stands in for the body's natural mid-cycle LH surge, prompting the final maturation of the egg before it is retrieved; the hormone is also used for ovulation induction and to help support the luteal phase ^[1][3]. A phase III trial in Japanese women undergoing ovulation induction found that recombinant hCG was non-inferior to traditional urinary hCG for triggering ovulation, with a comparable safety profile ^[2].

Choriogonadotropin alfa is a prescription biologic approved by drug regulators including the United States Food and Drug Administration and the European Medicines Agency. It is supplied as a prefilled solution for subcutaneous injection and is administered under medical supervision as part of a structured fertility protocol.

Choriogonadotropin alfa is prescription only. In women undergoing fertility treatment the main risk is ovarian hyperstimulation syndrome, which can cause swollen painful ovaries, fluid buildup and in severe cases clotting and breathing problems, and there is a raised chance of multiple pregnancy. Injection site reactions, headache and abdominal discomfort are common. In men it raises estrogen as testosterone climbs, which can bring on breast tenderness or gynecomastia. It should be avoided in hormone sensitive cancers, primary gonadal failure and undiagnosed abnormal genital bleeding, and it is timed carefully with monitoring during stimulation cycles.

Choriogonadotropin alfa is a recombinant form of human chorionic gonadotropin developed to replace the traditional product extracted and purified from the urine of pregnant women. Manufactured using recombinant DNA technology in cultured mammalian cells, it was introduced around the turn of the millennium by Serono under the brand names Ovidrel in the United States and Ovitrelle in Europe, gaining approval in the United States in 2000.

The recombinant approach offered a highly consistent, well-characterized product delivered by a convenient subcutaneous injection, in contrast to the intramuscular injections typical of the older urinary preparations. In reproductive medicine it is used to imitate the natural mid-cycle surge of luteinizing hormone, triggering the final maturation and release of the egg. Its arrival was part of a broader shift in fertility treatment toward recombinant gonadotropins that reduced reliance on donated human urine as a raw material.

Choriogonadotropin alfa is well regarded in assisted reproduction as a clean, reliable trigger for final oocyte maturation, appreciated for its manufacturing consistency and the comfort of a ready-to-use subcutaneous injection. Comparative clinical work has found that recombinant hCG performs as effectively as the older urinary product for triggering follicular maturation, with similar numbers of oocytes retrieved and comparable pregnancy rates, which reassured clinicians adopting it.

Because it acts on the same LHCG receptor as natural luteinizing hormone, it faithfully reproduces the physiological signal that drives ovulation and formation of the progesterone-secreting corpus luteum. The same receptor activity in testicular Leydig cells underlies its use in certain male endocrine settings. Its standing reflects both proven equivalence to established therapy and the practical and safety advantages of a recombinant, animal-source-free product.